10BQ5 tube substitution?

[EWBrown]

10BQ5s (and 8BQ5s) are identical to 6BQ5s, except for the filament voltage, which is 10.6 V AC or DC, at 450 mA each tube. So they are not a direct "plug and play" substitute, you will need to get 10.6V and the easiest way is a wall wart transformer. Either AC or DC is OK, and an easy way is to use a 12V DC wall wart, and drop the loaded output using a couple of resistors, or an LM317 regulator set up for 10.6 VDC (takes two resistors).

An alternative low cost 6BQ5 / EL84 substitute is the Russian made 6P14P, these show up on e-bay from sellers over there as well as in teh USA. The Chinese made tubes are "variable" in quality, some are very good, some are truly horrible...

/ed B in NH